I'm with NeonKnight maps for gaming need to be clear and understandable with just enough detail to put you in the mood. With that in mind, I would say that making the excavated areas much lighter than the background rock would be a good idea. It would make it easier to tell where you can walk and where you can't. You might also want to put some little transparency where the tunnels overlap to make it clear that the tunnel underneath is traverseable. Otherwise brightening the lava to show that it's really hot would be a good idea as well as putting some glow effect around it to display that it's casting light. As for the rest of the map, it looks great. Good work.